Flexible and sensitive foot pad for sole distributed force detection

We develop highly flexible and compressible 3D interconnected porous PDMS structures by using sugar cubes as templates. The porous structures can be compressed to more than 80% without any side-wall buckling comparable with bulk polymers. Force sensitive resistors were fabricated by filtration of the CNT solution inside the porous structure of PDMS. We found that sufficient acid treatment can increase the adhesion and bonding between CNTs and PDMS. Force sensitive resistors respond the applied pressure and compressive strains by high linearity (R²>0.97) and sensitivity (GFs>2) with a reliable manner. Finally, as an application of our force sensitive resistors, a flexible foot pad containing force sensitive resistors arrays is developed for the foot sole distributed force detection.